The present invention relates to polymers bearing nitrogen groups and their use as additives which impart an improved viscosity index and dispersing power to lubricating oils.
In U.S. Pat. No. 3,752,794, there are disclosed copolymers of para-tert.-butylstyrene and vinylpyridine to increase the viscosity index and the dispersing power of lubricating oils. These copolymers are obtained by radical polymerization and have a wide molecular weight distribution, making them sensitive to shear and having little action on the thickening power of lubricating oils.
The present invention provides new polymers which can be used as additives to improve the viscosity index and the dispersing power of lubricating oils.
It is, therefore, an object of the present invention to provide new polymer lubricating oil additives which impart to lubricating oils an increased viscosity index and dispersing power.
It is also an object of the present invention to provide lubricating oils of enhanced viscosity index and dispersing power, containing a polymer additive of the invention.
Other objects will be apparent to those skilled in the art from the present description.